error in text field? or is it jus me...

Hello I'm new to EJS and I run a Mac with OS 10.8.2 and Java SE 6. I find a weird behavior when I try to change the numerical value of some data on a text field. Namely the background changes to yellow, but the numerical change does not affect the dynamics at all. First I thought this was due to my little expertise, however I keep observing this behaviour in other simulations that come with the installation. For example, take the one called /ModellinfScience/Ch04_Drawing/BatonThrow.xmlThe simulation responds to the slider action, but changing the value of w on the text field has no effect (beyond changing the wintow to yellow). This happens to me with any .jar simulation edited with EJS (even others I downloaded from the web). It does not happen however with other simulations, like for example the ones in http://phet.colorado.edu/en/simulations/category/physics